While a host device accesses data on a primary system, data storage replication maintains a copy of the data on a secondary system. In particular, as the host device writes new data to the primary system, the write operation is also performed on the secondary system thus providing data redundancy.
If access to data on the primary system is lost, the secondary system provides manual failover capability. That is, a human administrator is able to change the secondary system from a read only mode to a read/write mode, thus enabling the host device to continue to access the data (e.g., to write new data) using the secondary system.